Python，在解析JSON对象时正确处理键错误

假设我想解析100个json对象，并从对象中提取某个元素，例如“author”：“Mark Twain”

如果100个json对象中有1个缺少信息并且没有“author”键，则会在停止程序时抛出一个键错误

处理这个问题的最佳方式是什么

此外，如果json对象中存在冗余，例如，存在名为“authorFirstName”：“Mark”和“authorlastName”：“Twain”的键， 在缺少“author”的情况下，是否有方法使用这些键而不是原始的“author”键？

如果键存在，可以使用

dict.get（'key'，default=None）

获取值

假设authors.json文件如下：

[
  {
    "author": "Mark Twain"
  },
  {
    "authorFirstName": "Mark",
    "authorLastName": "Twain"
  },
  {
    "noauthor": "error"
  }
]

您可以使用以下命令

import json

people = json.load(open("authors.json"))

for person in people:
    author = person.get('author')
    # If there is no author key then author will be None
    if not author:
        # Try to get the first name and last name
        fname, lname = person.get('authorFirstName'), person.get('authorLastName')
        # If both first name and last name keys were present, then combine the data into a single author name
        if fname and lname:
            author = "{} {}".format(fname, lname)

    # Now we either have an author because the author key existed, or we built it from the first and last names.
    if author is not None:
        print("Author is {}".format(author))
    else:
        print("{} does not have an author".format(person))

输出

Author is Mark Twain
Author is Mark Twain
{u'noauthor': u'error'} does not have an author

如果键存在，可以使用

dict.get（'key'，default=None）

获取值

假设authors.json文件如下：

[
  {
    "author": "Mark Twain"
  },
  {
    "authorFirstName": "Mark",
    "authorLastName": "Twain"
  },
  {
    "noauthor": "error"
  }
]

您可以使用以下命令

import json

people = json.load(open("authors.json"))

for person in people:
    author = person.get('author')
    # If there is no author key then author will be None
    if not author:
        # Try to get the first name and last name
        fname, lname = person.get('authorFirstName'), person.get('authorLastName')
        # If both first name and last name keys were present, then combine the data into a single author name
        if fname and lname:
            author = "{} {}".format(fname, lname)

    # Now we either have an author because the author key existed, or we built it from the first and last names.
    if author is not None:
        print("Author is {}".format(author))
    else:
        print("{} does not have an author".format(person))

输出

Author is Mark Twain
Author is Mark Twain
{u'noauthor': u'error'} does not have an author

---

根据您的要求，

如果author为None:

可能更合适。如果

author

为

False

（在JSON中为

False

）、

、
0
或
0.00
，甚至
[]
或
{code>
也会显示错误。我认为
为null
（当然，在Python中是
None
）。根据您的要求，
如果author是None:
可能更合适。如果
author
是
False
（在JSON中是
False
）、
”、
0
、或
0.00
，甚至
[]
或
{}
也是。我认为
null
（当然，在Python中，
None
）。